Describe and explain how the solubilities of the sulfates of the Group II elements change down the group.
Use the data above to calculate the values of $\Delta H^\circ_{\text{solution}}$ for $\text{Mg(OH)}_2$ and for $\text{Sr(OH)}_2$.
Use your answers in (i) to decide whether $\text{Sr(OH)}_2$ is more or less soluble in water than $\text{Mg(OH)}_2$. State any assumptions you have made.
Suggest whether $\text{Sr(OH)}_2$ would be more soluble or less soluble in hot water than in cold water. Explain your reasoning.
The table below shows some enthalpy changes for magnesium and strontium compounds.
Calcium hydroxide, $\text{Ca(OH)}_2$, is only slightly soluble in water.
Write the expression for $K_{sp}$ of calcium hydroxide, and state its units.
$25.0\,\text{cm}^3$ of a saturated solution of $\text{Ca(OH)}_2$ needed $21.0\,\text{cm}^3$ of $0.0500\,\text{mol dm}^{-3}$ $\text{HCl}$ for complete neutralisation. Calculate $[\text{OH}^-(\text{aq})]$ and $[\text{Ca}^{2+}(\text{aq})]$ in the saturated solution, and then calculate a value for $K_{sp}$.
How does the solubility of $\text{Ca(OH)}_2$ in $0.1\,\text{mol dm}^{-3}$ $\text{NaOH}$ compare with its solubility in water? Explain your answer.